Air Pollution In Beijing

Feng Li

This combination of photos shows (bottom) the Tiananmen Square during severe pollution on January 23, 2013, and the same view (top) taken during clear weather on January 24, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

This combination of photos shows (bottom) the Tiananmen Square during severe pollution on January 23, 2013, and the same view (top) taken during clear weather on January 24, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Lintao Zhang

A woman wearing a mask walks past the CCTV Building during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels as smog blanketed the city.

A woman wearing a mask walks past the CCTV Building during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels as smog blanketed the city.

Air Pollution In Beijing

Feng Li

A tourist and her daughter wearing the masks visit the Tiananmen Square at dangerous levels of air pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

A tourist and her daughter wearing the masks visit the Tiananmen Square at dangerous levels of air pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

A tourist wearing the mask visits the Tiananmen Square at dangerous levels of air pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

A tourist wearing the mask visits the Tiananmen Square at dangerous levels of air pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

Beijing residents wearing the masks ride a motorcycle through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Beijing residents wearing the masks ride a motorcycle through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

A man rides a tricycle to transport coal through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

A man rides a tricycle to transport coal through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

A worker wearing the mask sits outside the construction site during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

A worker wearing the mask sits outside the construction site during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

Beijing residents take bus through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Beijing residents take bus through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

A tourist wearing the mask visits the Tiananmen Square at dangerous levels of air pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

A tourist wearing the mask visits the Tiananmen Square at dangerous levels of air pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

A man wearing the mask rides a bicycle through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

A man wearing the mask rides a bicycle through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

A woman wearing the scarf ride a bicycle through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

A woman wearing the scarf ride a bicycle through a panda sculpture during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

A men wearing the mask walks under the trees during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

A men wearing the mask walks under the trees during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

Air Pollution In Beijing

Feng Li

A men wearing the mask walks under the trees during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.

A men wearing the mask walks under the trees during severe pollution on January 23, 2013 in Beijing, China. The air quality in Beijing on Wednesday hit serious levels again, as smog blanketed the city.